Wales vs Cymru

Wales and Cymru both are nouns.

Word	Noun	Adjective	Verb	Adverb
Wales	Yes	No	No	No
Cymru	Yes	No	No	No

As nouns, Wales and Cymru are synonyms defined as:

Wales and Cymru: one of the four countries that make up the United Kingdom of Great Britain and Northern Ireland; during Roman times the region was known as Cambria

Other synonyms of Wales include Cambria.

Wales (noun)	Cymru (noun)
one of the four countries that make up the United Kingdom of Great Britain and Northern Ireland; during Roman times the region was known as Cambria	one of the four countries that make up the United Kingdom of Great Britain and Northern Ireland; during Roman times the region was known as Cambria